铅锌烟灰为原料制备氯化锌和电铅工艺研究

Study on new technology of preparation of zinc chloride by acid leaching and purifying by electrodeposition method

研究了炼铅厂铅锌烟灰作原料,以盐酸浸取并以高锰酸钾氧化Fe^(2+)、Mn^(2+),电积法分段分离Cu^(2+)、Pb^(2+)、Cd^(2+),两步法生产氯化锌的新方法。以高的锌浸出率、低的铅浸出率,Fe^(2+)、Mn^(2+)、Cu^(2+)、Pb^(2+)、Cd^(2+)除杂最彻底,处理成本最低为考察目标,确定了最佳的工艺条件:40 g铅锌烟灰、71 m L浓盐酸与130 m L水于30℃下酸浸50 min后,加高锰酸钾16.7 mg,10℃下继续反应2 h后过滤,滤液作阴极液分3段进行电沉积除Cu^(2+)、Pb^(2+)、Cd^(2+),每段电积时间控制为10 min,3段电积的电极电位分别控制为0.09、-0.37、-0.64 V,阴极液温度控制为30℃,电积30 min后,制得1.64 mol/L的氯化锌溶液。上述工艺中,锌的酸浸率达95.41%,用制备的氯化锌溶液生产氧化锌,产品杂质含量满足GB/T 19589—2004《纳米氧化锌》一级品的要求,浸出液中含量较多的金属离子通过分段电积回收,降低了锌灰浸出液除杂的成本,并使杂质离子实现了资源化,工艺更加绿色经济。

A new technology of preparing zinc chloride was studied.The technology taking zinc ash from a lead smelter as raw material applied a two-step method as below：leaching zinc ash by hydrochloric acid,oxidizing Fe^2＋ and Mn^2＋ by potassium permanganate,and separating Cd^2＋,Pb^2＋,and Cu^2＋by electrodeposition method.To get the high leaching rate of zinc,the low leaching rate of Pb and the thoroughly removing of Mn,Fe,Pb,Cd,and Cu elements,the optimum experimental acid leaching and purification conditions were as follows：after 40 g lead-zinc ash leached by the mixed acid including 71 m L concentrated hydrochloric acid and 130 m L water for 50 min at 30 ℃,0.017 g KMn O4 was added into the solution to continue the reaction for 2 h at 10 ℃,and then electrodeposited Cu,Pb,and Cd on the potential of 0.09 V for 10 min,then-0.37 V for 10 min,and then-0.64 V for 10 min in the filtration,and finally the zinc chloride solution with the concentration of 1.64 mol/L was obtained.Under above conditions,the leaching rate of zinc was 95.41%,the impurity ion content in zinc chloride solution met the requirements of the first grade of Nano-sized Zinc Oxide,GB/T 19589—2004.The metal ions in the leaching solution were recovered by segmented electrodeposition,thus realized the cost reduction of impurity removal,changing impurity ions into resource, and the process being more green and economical.